PPRuNe Forums - View Single Post - Arrow PA-28 Experienced In-Flight Break-Up
Old 18th Nov 2007, 08:02
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SNS3Guppy
 
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Well from now on I'm going to fly around in a Spitfire, now there's an aircraft that won't be suffering in flight break up.
Don't want to burst your bubble or anything, but here's a brief, partial list of a few Spitfires that did...

Mar 39...Mk I....K9838...Structural failure in dive.
Jan 41...Mk I....N3191...Both wings broke off in dive.
Jul 41...Mk I....X4354...Port wing broke off in dive.
Aug 41...Mk I....X4381...Starboard wing broke off in dive.
Mar 41...Mk I....X4421...Both wings broke off in dive pullout.
Jul 41...Mk I....X4662...Stbd wing broke off in dive pullout.
Jun 41...Mk I....X4680...Wings/tail broke off in dive pullout.
Nov 42...Mk I....X4621...Failed to recover from dive.
Apr 43...Mk II...P7352...Broke up in dive.
Sep 41...Mk II...P7522...Both wings broke off in dive.
Jun 43...Mk V....BL531...Both wings broke off in dive.
Feb 42...Mk V....AA876...Disintegrated in dive.
Jul 43...Mk V....BL389...Pilot thrown from aircraft in dive.
Jan 43...Mk IX...BS251...Structural failure in dive.
May 43...Mk IX...BS385...Structural failure in dive.
Aug 43...Mk IX...BS441...Disintegrated in dive.
Oct 46...Mk IX...PL387...Disintegrated in dive.
Jan 48...Mk XVI..SL724...Crashed after recovery from dive.
Sep 48...Mk XVI..TD119...Crashed after recovery from dive.
Aug 42...Mk I....N3284...Broke up in flight.
Aug 41...Mk I....N3286...Broke up in flight.
Sep 40...Mk I....P9546...Structural failure in flight.
May 42...Mk I....P9309...Lost wing in flight.
Apr 43...Mk I....X4234...Lost wing in spin.
Sep 42...Mk I....P9322...Broke up in flight.
Aug 43...Mk I....R6706...Aileron failure which led to crash.
Jan 43...Mk I....X4854...Starboard wing broke off in flight.
Nov 40...Mk II...P7593...Stbd wing and tail broke off in flight.
Dec 41...Mk II...P8183...Port wing broke off in flight.
Jun 42...Mk II...P8644...Starboard wing broke off in flight.
May 41...Mk II...N8245...Structural failure in flight.
Feb 44...Mk II...P7911...Flap failure which led to crash.
Sep 42...Mk V....AD555...Flap failure which led to crash.
Mar 44...Mk V....BL303...Flap failure which led to crash.
Dec 41...Mk V....BL407...Structural failure suspected.
Jun 42...Mk V....AB172...Structural failure in flight.
Mar 43...Mk V....AA970...Structural failure in flight.
Jun 43...Mk V....BL290...Port wing broke off in flight.
May 43...Mk V....BR627...Port wing failed in spin.
Oct 41...Mk IV...AA801...Structural failure in flight.
Feb 43...Mk IX...BS404...Structural failure in spin.
Feb 45...Mk IX...MH349...Wing failed during aerobatics.

(reference Spitfire: The History)

In Spitfire at War, by Alfred Price, Eric Newton is quoted as saying:

"Out of a total of 121 serious or major accidents to Spifires reported to us between the begining of 1941 and the end of the war, 68 involved structural failure in the air. Initially the most common reason for such failures, with 22 instances in 1941 and 1942, was aileron instability. The symptoms were not at all clear cut: the aircraft were usually diving at high speed when they simply fell to pieces. Only after one of the pilots had survived this traumatic experience and parachuted successfully were we able to find the cause. During his dive he saw both of his ailerons suddenly flip up, producing an extremely violent pitch- up which caused the wing to fail and the aircraft to break up. In collaboration with RAE we did a lot of tests and found that aileron up- float was made possible by stretch in the control cables; in those days tensioning was a hit or miss affair with no compensation for temperature. On our recommendation the RAF introduced a tensometer which ensured accurate tensioning of the controls; this, and the simultaneous introduction of metal surfaced ailerons ('42/'43), cured almost all the cases of aileron instability in the Spitfire.

The next most serious cause of structural failure in the Spitfire was pilots overstressing the airframe. She was extremely responsive on the controls and one must remember that in those days there was no accelerometer to tell the pilot how close he was to the limit. So it was not difficult to exceed the aircraft's 10G ultimate stress factor (what was the 109's?- Berkshire) during combat or when pulling out from a high speed dive; during the war we were able to put down 46 major accidents to this cause, though undoubtedly there were many other occasions when it happened and we did not see the wreckage. Incidentally, if there was a structural failure in the Spitfire it was almost inevitably the wing that went; the fuselage was far less likely to fail first (the same for most low wing monoplane fighters?-except the Typhoon?- Berkshire).

I once asked a very senior RAF officer why the accelerometer- technically a simple instrument- was not introduced during the war. He replied that he was sure it would have an adverse effect on the fighting spirit of the pilots (same was said re the parachute in WW1!- Berkshire).

Whether that would have been so I cannot say. But I do know that when they finally introduced the accelerometer into service in the Hunter in 1954, and began educating the pilots on structural limitations and the dangers of overstressing, accidents to this cause virtually ceased.

After structural failure the next largest category of accidents proved on investigation to have followed loss of control by the pilot (36 cases). Of these 20 occured in cloud and could be put down to pilot error; one must remember that in the rush to get pilots operational instrument training was not up to peacetime standards. A further 13 accidents were shown to have been caused by oxygen starvation; the oxygen system had been used incorrectly with the result that the pilot had passed out and the aircraft had crashed. As a result of our investigations the system was modified to make it easier to operate.

The remaining 3 accidents in the loss of control category were initiated by the pilot pulling excessive G and blacking himself out."


Whereas a tough, solidly built tactical airplane designed and stressed for maneuvering and violent aerobatics can experience those failures while being flown by a pilot who is trained and capable above and beyond what the basic private pilot syllabus provides, how much more careful ought one to be with the modest Arrow or 172? Yes indeedy, they all most certainly do break.
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